<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<style type="text/css">
    .father {

        width: 300px; height:150px;

        position: relative;

        background-color: green;
    }

    .son {
        position: absolute;
        top: 0; right: 0; bottom: 0; left: 0;
        width: 200px; height: 100px;
        margin: auto;
        background-color: red;
    }

</style>
<body>
    <div class="father">
        <div class="son"></div>
    </div>
</body>
</html>